The present invention relates to a light measuring device such as a chromatometer, a spectrometer, a colorimeter, a glossmeter, a white color meter, and the like.
In conventional types of light measuring devices of the kind mentioned above, a plurality of mechanisms are utilized to perform both spectrogram and alternative radiation procedures, and in view of this fact, the structure is very complicated and at the same time must accordingly have a large size and must be very expensive.
Furthermore, since the conventional types of devices use a plurality of mechanisms, there are introduced many trouble areas wherein the possibilities for generating errors against the measured values are increased, and thus it is difficult to obtain high reliable values.
In general, zero adjustment for use in making a measurement is manually performed when the adjustment is started, so that when the measuring time is continued for a long period, some variations of the light source and the light receiver are realized and thus it is difficult to obtain a correct measuring value differing from the zero adjustment initially obtained. At the same time, even if a zero adjustment can be made at a specified period of time, say midway through the metering operation, this operation is not performed due to the problems in making such a measurement.
It is therefore an object of the present invention to provide a photometer in which the disadvantages found in the conventional photometers are overcome and an extremely, highly reliable measuring value can be obtained.
It is another object of the present invention to provide a photometer in which both spectrogram and alternative radiation measurements may be performed by the rotation of one rotary plate provided with one mechanism, i.e. at least one filter element.
It is yet another object of the present invention to provide a photometer in which the zero adjustment may be automatically performed at every time a measurement is made with the variations of the light source and the light receiving element.
It is still a further object of the present invention to provide a photometer which possesses a simplified structure and its miniturization may be made to promote a rapid measuring operation.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description.
According to the present invention, a half-mirror and a reflection plate are arranged in front of a light source to form one light passage extending to a reference plate and another light passage extending to a sample. A rotary plate provided with a plurality of filters having different wave lengths is installed in both light passages and an alternate radiation against the reference plate and the sample is caused by the rotation of the rotary plate.
The form of installation of the filters in the rotary plate of the present invention is made such that either one filter is alternatively positioned in one light passage extending to a reference plate or the other light passage extending to the sample, or a plurality of filters having different wave lengths which are installed in the rotary plate are initially positioned continuously in a light passage on the reference plate, and then continuously located in the light passage of the sample.